1. Field of the Invention
The present invention generally relates to a toner cartridge, a developing unit, and an image forming apparatus.
2. Description of the Related Art
FIG. 15 is a side cross-sectional view of a waste toner chamber 105 of a conventional toner cartridge 102 for use in an electrophotographic printer. FIG. 16 is a perspective view of a lid mounted to close one end of the toner cartridge 102 that extends in a longitudinal direction. The toner cartridge 102 includes a fresh toner chamber 104 that holds fresh toner therein and a waste toner chamber 105 that holds waste toner therein. The fresh toner chamber 104 and waste toner chamber 105 extend in their longitudinal directions and are divided by a longitudinally extending partition wall. The fresh toner chamber 104 includes an agitating bar 106 for agitating the fresh toner in the fresh toner chamber 104. The agitating bar 106 is connected to a drive gear 107, which is driven to rotate by an external drive source. The waste toner chamber 105 incorporates a screw conveyor 143 that moves the waste toner, collected form the developing unit, into the waste toner chamber 105.
With the aforementioned toner cartridge, the agitating bar 106 in the fresh toner chamber 104 and the screw conveyor 143 need to be driven by separate drive sources. Driving the toner agitating bar 106 and screw conveyor 143 by separate drive sources makes the construction complicated and results in an increased number of parts.